What is the LAG for a loma for a house that has a window well. Is it the grade. On the outside of the well or the inside of the well. Seems like the well is part of the structure and the LAG would be for the grade on the outside. I have not found anything on the FEMA website that tells me how it should be.

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Flood water has to get up to the hight of the window well before it gets into the window....lowest grade next to the window well is what we use for LAG.

I would agree with this and it makes sense (even though that is often not a required element). Just like a home with a crawl space where the water could enter the crawlspace through foundation vents or the access, the floor of the crawlspace is not considered the LAG. What ends up getting us from time to time, is that attached stairs and deck supports count as part of the structure for the determination of the LAG for a LOMA.

FEMA LOMA Determination Requirements:

  • LOMA Requests Involving One or More Structures: For a LOMA to be issued by FEMA to remove one or more structures from the SFHA, the NFIP regulations require that the lowest adjacent grade (the lowest ground touching the structure) be at or above the BFE.
Ei found a fema technical publication on line the explains it. The lag is bottom of the well but if the original ground was higher you can get a loma based on intervening natural ground. I assume that if the natural ground was still to low you would just have to have homeowner buck up for a loma-f. Only word of advice is to make sure the city loma guy will sign the community acknowledgment form. Maybe I will do them right. Thanks for input

I had this discussion with a FEMA tech at the first of last year.  He claimed that the LAG was the bottom of the access well to the crawl space. I could not get him to budge and the LOMA was denied.

Since then the new EC has come out with Diagram 2B. That diagram calls for the LAG at the top of the walk out. Therefore the bottom of a window well for a basement (below existing ground) is not the LAG.

We resubmitted and have successfully received a removal for last years denial.


I think it would be Diagram 2B and the Grade would be the ground, based on the Diagram in the instructions. Since the finished floor would be the controlling factor for being in or out of the flood, the LAG by the window would prevent surface water from getting into the window well (except for rainwater straight down.)

Good question.



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